Mechanism of Curie-Point Writing in Thin Films of Manganese Bismuth

This paper presents the first detailed calculation of the demagnetizing field using the measured temperature dependence of the magnetization of manganese bismuth films and assuming realistic time-dependent temperature distributions. It yields calculated demagnetizing fields that are in good agreement with the measured values of field required to erase written spots in manganese bismuth in either of its two phases. Based on the agreement between measured erasure field and calculated demagnetizing field, we conclude that the demagnetizing field model of Curie-point writing is justifiable. The results can be used to explain the previously reported partial erasure characteristics of this material.